There are three things to purchase online for your trip: Milepost - which is great for history and maps as you travel; Mike and Terri Church's book 'Alaskan Camping' which includes Canada and the Yukon; and the TourSaver 2/1 Coupon Book. That's all you need.....don't even need reservations....except we did make two during our summer trip - for Denali Nat'l Park at the farthest campground you can drive, Teklanika and for the July 4 weekend - Alaskans like to camp, too. We only made those a couple weeks prior as we were traveling to better judge when we be in the areas.
Alaska talk of the forums begin in earnest during the winter months. Read, read, read. Have fun planning. Allow plenty of time to explore Canada, too. Some places are just as beautiful as Alaska.
Full-timed for 16 Years . . . Back in S&B Again
Traveled 8 yr in a 2004 Newmar Dutch Star 40' Diesel
& 8 yr in a 33' Travel Supreme 5th wheel